1. Field of the Invention
THIS INVENTION relates to improvements in drills for piles. The term "piles" shall be used to include in-situ cast piles; tension piles; rock bolts; and ground-or-sand anchors.
The invention also relates to improvements in drills for soil stabilization.
2. Prior Art
On many building sites, compression piles having diameters of at least 300 mm are either driven into the ground, or cast in-situ, to provide sufficient bearing load for the building foundation. The drills required for the holes for the cast piles must be mounted on large prime-movers, which are expensive, and their access can be limited on the sites.
The load strength of the foundation piles used in buildings and civil engineering works is also dependent on the properties of the soil surrounding the piles. If the soil has a composition which includes e.g. clay or sand, or is full of fissures or cracks, the load strength of the piles will be much lower than if they were supported by rock.